Preparation Andapplication Ofadditional Liquid Silicone Rubber In LED Encapsulation Material

LED has been widely used in various industries due to their efficiency and environment friendly. With the improvement of LED power and brightness, we put forward more requirements towards LED encapsulation material. At present the market of LED encapsulation material with excellent performance is dominated by foreign manufacturers. Based on this situation, we got down to research this kind of material detailedly.We aim to obtain additional liquid silicone rubber with outstanding physical and chemical properties, and to study the influence of the two components: rubber compound and cross-linking agent on the properties of the target products. We adopted two methods to prepare the rubber compound. The first method is mixing phenyl polysilicone which was obtained by hydrolysis-condensation of Ph2SiCl2, D4 and MMVi via anionic ring-opening polymerization reaction to prepare rubber compound V1. The second method is mixing D4 and prepolymer of rubber compound (Pre-V2) gained by hydrolysis-condensation of different kinds of chlorosilianes by means of the same reaction to synthetize rubber compound V2. Then we studied the preparation of cross-linking agent. Analogously, prepolymer of cross-linking agent (Pre-H) was obtained with method of hydrolysis-condensation of different kinds of chlorosilianes. Afterwards, we resort cation ring-opening reaction to prepare cross-linking agents H1, H2 and H3 with the reactants of Pre-H, D4 and commercial high H-content silicone oil. All of the products were characterized by IR, UV, 1HNMR, determination of groups content including Vi, Ph and H contents, viscosity and refraction indexes.Finally, we prepared additional liquid silicone rubber (LSR) by hydrosilylation reaction with rubber compound and cross-linking agent in the catalysis of Pt complex. Also the factors of LSR mechanical property were discussed in detail. When we added MQ silicone resin made by our laboratory to this system,the best mechanical datas were obtained. Additionally, we analysed adhesion to base material and thermal weightloss rate of LSR, and the results showed that this kind of material had excellent cohesiveness and thermostability.